The present invention relates to the field of electrical connectors of so-called low force of insertion, or zero force of insertion, more particularly with pin/lyre contacts.
To connect a layer of flexible cables to a rigid support of the printed card type, users require connectors needing a minimum insertion and blocking force, this latter remaining a necessity to permit any inadvertent disconnection. More generally, connectors are sought which will permit avoiding any accidental disconnection.
There is known for example a connector of zero insertion force described in U.S. Pat. No. 4,718,859, provided to receive a layer of cables.
Such a connector comprises two blocks:
a fixed block, generally connected to a support and provided for this purpose with blade contacts with a plug which are welded to the support, and PA1 a movable block which coacts with the fixed block to immobilize the cables of the layer and ensuring contact between the cables of this layer and the blades, this requiring no insertion effort of the layer.
The movable block is mounted on the fixed block by translatory movement, guide means ensuring a suitable positioning of the two parts. The layer is then inserted between the two blocks. It then suffices to pivot the movable block relative to the fixed block to ensure pressing one portion of the blades against the cables, thereby ensuring the electrical connection. The locking is simultaneously ensured because any displacement in translation of the movable block relative to the fixed block is prevented.
The problem solved by this patent is that of the variations of thickness of the various layers to be inserted in this connector. Thus, these variations give rise to loss of pressure force of the plugs of the fixed block on the cables of the layer, unless different models are provided, each applicable to a type of layer. Given the very low sales price of these connectors, it would be of interest to provide a connector permitting receiving different thicknesses of layers of cables.
To solve this problem about different thicknesses, the base as specified in this American Patent have blades with a particular C-shaped profile, with offset ends thus forming two offset contact points, above and below the layer. Branches of the C shaped profile have a sufficient flexibility and adjust to thickness variations. The layer presents an S-shaped deformation when it is thin and the layer remains substantially flat when it is thick. The contact pressure is obtained in the same manner in both cases and only a contact at two points is possible.